SPACE ENVIRONMENTS SEMINAR—PART II

The second AIAA space environments seminar will focus on Spacecraft Charging and the effects of Micrometeroids and Space Debris. Each of these interactions are discussed below.

Spacecraft Charging:  Spacecraft Charging is caused by the interaction of charged particles with external spacecraft surfaces (surface charging) and, in the case of internal charging, with the buildup of charge in and on dielectrics and surfaces within the vehicle.  The buildup of charge can affect particle measurements or can lead to arcing between surfaces or breakdown in dielectrics. The talk will review briefly the environments that can cause significant charging, develop the equations for surface and internal charging, review the effects of arcing, and discuss the methods for limiting charging effects with emphasis on the NASA 4002 series of guidelines.

Micrometeroids and Space Debris: Micrometeroid and space debris impacts on space vehicles can of course cause significant damage and even destroy them. Returned surfaces from Earth-orbiting spacecraft have often provided examples of pitting and indeed the windows on the Space Shuttle have shown cracks due to impacts. In this talk, following a review of the ambient meteoroid environment and the growing space debris environment at Earth, we will review the equations for computing the effects of hypervelocity impacts. These will be divided into single surface and double surfaces (e.g., Whipple shields). Methods such as the Whipple shield for protecting spacecraft and the computations necessary to evaluate an overall meteoroid shielding design will be presented.

Tentative Agenda: (All Time PDT (GMT -0700)) (US and Canada)

1000 Welcome

1005 Presentation Part I: Spacecraft Charging

1205 Intermission | Lunch Break (Lunch is on attendee's own.)

1305 Presentation Part II: Micrometeroids/Space Debris

1505 Additional Q&A (if needed) / adjourn.

Dr. Garrett has a doctorate in Space Physics and Astronomy from Rice University. He has over 150 publications on the space environment and its effects with specific emphasis in the areas of atmospheric physics, the low earth ionosphere, radiation, micrometeoroids, space plasma environments, and effects on materials and systems in space. While on active duty in the Air Force he served as Project Scientist for the highly successful SCATHA program which studied the effects of charging on spacecraft. For this he was awarded the Harold Brown Award, the Air Force’s highest scientific award. In 1992, he was selected for a joint DoD/NASA assignment at the Pentagon as part of the Ballistic Missile Defense Organization where he acted as the Deputy Program Manager for the Clementine Lunar Mission and Program Manager for the Clementine InterStage Adapter Satellite (ISAS). For contributions to these missions, he was awarded NASA's Medal for Exceptional Engineering Achievement. After a 30 years career in the USAF Reserves, he retired in 2002 as a full Colonel and was awarded the AF Legion of Merit. During his 43-year career at JPL, he has been responsible for defining the space environment and its effects on the reliability of many NASA missions. He has also published several textbooks on the space environment and its impact on spacecraft design and reliability. Dr. Garrett is an international consultant on the terrestrial and interplanetary space environments and spacecraft reliability having worked for INTELSAT, L’Garde, NASDA, LORAL, CNES, and other organizations. In 2006 Dr. Garrett received NASA’s Exceptional Service Medal for “his achievements in advancing the understanding of space environments and effects.” Dr. Garrett co-authored with Mr. Albert Whittlesey the primary NASA standard on spacecraft surface and internal charging for earth missions. Dr. Garrett retired from JPL in January of 2023. He was made a Fellow of the AIAA in 2019 and received the AIAA James Van Allen Space Environments Award in 2022.